chrischamberlin Posted February 26, 2012 Share Posted February 26, 2012 Hi all, Apologies in advance for being daft!! Having started my X1X CRT for the 1st time a minute ago, the engine screamed immediately and the wheels engaged (luckily the car was on a box so it didnt run away!!) In order to get the idling ok without the wheels spinning I had to hold the throttle on the Tx to full break. This stopped the wheels spinning and enabled me to get the rich idle recommended on the engine break in instructuions but had top hold break on throughout the entire 1st tank. Can anyone help, as I thought the engine should idle with the Tx throttle in the middle / neutral position? Thanks in advance. Quote Link to comment Share on other sites More sharing options...
Rusty1103 Posted February 26, 2012 Share Posted February 26, 2012 Is your carb open around 1mm? Also take the servo horn off and put the tx and rx on. Put the trim dial on your tx to the middle then put the horn back on so that the brakes aren't being applied and neither is the throttle. This is where to start. Quote Link to comment Share on other sites More sharing options...
chrischamberlin Posted February 26, 2012 Author Share Posted February 26, 2012 Thanks Rusty, I was hoping the carb was set up to 1mm, as came RTR. How do I check the carb opening? Also what is the Servo horn? I am a complete newbie if you havent already guessed!!! Quote Link to comment Share on other sites More sharing options...
dbobd Posted February 26, 2012 Share Posted February 26, 2012 Gap in carb too big. Do what rusty says. Have your RX and TX on when you start the car, that ensures the throttle goes back to the correct position rather than it sitting open where you left it How do I check the carb opening?" Take the air filter off and look down the hole in the carb Quote Link to comment Share on other sites More sharing options...
dbobd Posted February 26, 2012 Share Posted February 26, 2012 Servo horn is the plastic <===> shaped thing on top of your servo that your brake and throttle linkage are attached to. Quote Link to comment Share on other sites More sharing options...
HATZY Posted February 26, 2012 Share Posted February 26, 2012 Servo horn is the plastic <===> shaped thing on top of your servo that your brake and throttle linkage are attached to. with a screw in the middle. remove the screw to take the horn off Quote Link to comment Share on other sites More sharing options...
soup Posted February 26, 2012 Share Posted February 26, 2012 Also what is the Servo horn? http://t3.gstatic.com/images?q=tbn:ANd9GcTrxm-ef0d45nbtmQm5SsO7L5W_KqwUjKFlIWuEchduovtFXBrgH7mCejX91w May be circular, a star, two at right angles etc etc. Quote Link to comment Share on other sites More sharing options...
anton Posted February 26, 2012 Share Posted February 26, 2012 Sounds like your servo links to the brake and trottle aren't setup properly (your idle screw adjustment might be a bit out too, but worry about that later) Best to start from the beginning... Terminology ... Servo horn = the plastic (or metal) arm that screws onto the top of the servo. It has holes in it that the links are attached to. Brake / trottle links = usually rigid metal wire links with either loops or plastic ball cups on them which go between the servo horn and either the carb or brakes. Carb = The engine carburettor - this controls the mixture of fuel and air going into the engine. Most nitro engines have a slide carb and all look and work pretty much the same way. The slide has a ball on it which connects to a link on the trottle / brake servo. When in the inner (closed position) the engine should just idle, when opened the engine should increase in revs. Air filter = Filters the air going into the engine! An oil soaked foam attached via a short rubber tube. Tx = transmitter Rx = Receiver Trim = An adjustment on the Tx which allows you to make fine adjustments to the servo's neutral position. End point adjustment = A setting on the Tx which allows you so set the maximum travel for each servo. You should be able to set the end point for each direction on each servo so that the servo is not straining against the links to go beyond the available travel. Set this too low and the servo won't move far enough. Set this too high and you'll strain the servo, possibly burning it out or damaging other components such as the carb. Take the servo horn off the servo and set the trim to neutral and open up the end point adjustments to 100% (this makes sure the servo is centered and has maximum travel available). Refit the servo horn as appropriate for your buggy (look in the instructions for this). First sort out the trottle - set the trottle link so that the carb slide is fully closed when the trottle on the tx is at neutral. You want the spring on the link to apply enough pressure to make the slide close fully (this will still leave a 1mm gap, depending now how your idle screw is set. The other side of the link on the servo horn should be pretty snug against the horn, so that when you open the throttle on the tx, the link is pulled and opens the carb. You will need to take off the airfilter tube from the carb to look down the hole and see if the carb is opening fully. You should find that it opens fully and you'll need to dial down your end point adjustment so that when the throttle is opened, the carb slide opens completely but isn't opening beyond that and putting strain on the carb or the servo. Now sort out the brakes - with the servo and tx in neutral, the links should be set so that the wheels can spin freely. Depending on the make of your buggy the links are adjusted by spacers on the links or knurled nuts which allow finger adjustments. You want to get the link adjusters set pretty close to the servo horn, so that the brakes are applied with minimal movement on the servo - that way, the servo can apply more pressure to the brakes if needed. Again, you'll probably need to dial back the end point adjustment so that the brakes come on nice and tight, but aren't putting undue strain on the servo or causing massive flex on the servo holder etc. Some brake links include lengths of fuel tube to give them a bit of flex and adjust the braking bias. You should now have brake and trottle links in the right place. Test this without the engine running to make sure the carb is opening and closing consistently and the brakes are coming on and off as appropriate. While you have the air filter off look to see what the gap is between the slide and the carb body (as others have mentioned around 1mm is a good starting point). Make sure you replace the air filter before starting up again. Hope this ramble helps!! Quote Link to comment Share on other sites More sharing options...
chrischamberlin Posted February 26, 2012 Author Share Posted February 26, 2012 Ok, Just returned from garage and thought i'd try the servo horn first (as easier!!). Unscrewed and removed servo horn, turned TX and RX on, set both trim dials to middle and reattached servo horn. When I started her up it was than before - the engine screamed again, wheels engaged and full brake would not stop wheels turning so covered exhaust to stall. Tried pulling air filter off engine but the rubber felt like it may snap and attached with zip tie, shall I simply snip the tie and remove? Also, if carb not 1mm open, do I need a special tool to adjust? Sorry for ruining your Sunday!! Quote Link to comment Share on other sites More sharing options...
anton Posted February 26, 2012 Share Posted February 26, 2012 Ok, Just returned from garage and thought i'd try the servo horn first (as easier!!). Unscrewed and removed servo horn, turned TX and RX on, set both trim dials to middle and reattached servo horn. When I started her up it was than before - the engine screamed again, wheels engaged and full brake would not stop wheels turning so covered exhaust to stall. Tried pulling air filter off engine but the rubber felt like it may snap and attached with zip tie, shall I simply snip the tie and remove? Also, if carb not 1mm open, do I need a special tool to adjust? Sorry for ruining your Sunday!! Not ruining anything, we have all been there. Just snip off the zip tie and pull the tube off. The carb has three screws on it - Two which adjust the mixture and one which adjusts the idle. These should take a small flat bladed screw driver to adust. See here for what scew is what ... http://rcchatzone.com/rcmasters.com/Images/CarbDiagram2.jpg Quote Link to comment Share on other sites More sharing options...
soup Posted February 26, 2012 Share Posted February 26, 2012 (edited) Tried pulling air filter off engine but the rubber felt like it may snap and attached with zip tie, shall I simply snip the tie and remove? Also, if carb not 1mm open, do I need a special tool to adjust? No special tool required to alter the idle just use a normal (thin bladed) screwdriver on the idle screw (should be about the middle of the carb).. Just, carefully, remove the zip tie and remove the filter (replacement zip ties are, about, Edited February 26, 2012 by soup Quote Link to comment Share on other sites More sharing options...
chrischamberlin Posted February 26, 2012 Author Share Posted February 26, 2012 Many thanks everyone, plenty to chew on now..... I confused the End poiint dials with Trim buttons earlier so will revisit servo set up prior to carb.... How do I guarantee the trims are set to the neutral position? Oh, and Anton - thats a cracking ramble! Quote Link to comment Share on other sites More sharing options...
HATZY Posted February 26, 2012 Share Posted February 26, 2012 Many thanks everyone, plenty to chew on now..... I confused the End poiint dials with Trim buttons earlier so will revisit servo set up prior to carb.... How do I guarantee the trims are set to the neutral position? Oh, and Anton - thats a cracking ramble! wehen you take the horn off, move the trim knob to the center, if its a dial itl have a line on it, if you dont know where the center point is turn it all the way in both directions then turn it back to the middle of those two points. with the trim centered you you can attatch the horn, taking care to ensure the carb gap is correct and the throttle linkage is the right length and the brake link is the right length to allow the car to freewheel but still have positive braking force. you may need to alter the trim slightly to make the splines line up exact Quote Link to comment Share on other sites More sharing options...
wiggy2k7 Posted February 26, 2012 Share Posted February 26, 2012 (edited) this vid might be of interest: you really need to do some kind of research into the running and workings of these nito cars, if not your gonna run into problems Have a read through some guides and watch some how to vids Edited February 26, 2012 by wiggy2k7 Quote Link to comment Share on other sites More sharing options...
HATZY Posted February 26, 2012 Share Posted February 26, 2012 you tube is packed full of how to vids. set youself some time to to just sit and watch some. you will watch 1 and then see another that looks interestin and so on Quote Link to comment Share on other sites More sharing options...
chrischamberlin Posted February 26, 2012 Author Share Posted February 26, 2012 Many thanks all. Managed to run through 3 sets of fuel idling, and got her moving slowly up and down the garden so fairly happy. It seems a good idea to look at a few youtube links before pushing it a little harder!! Quote Link to comment Share on other sites More sharing options...
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